Elements automatically named π by GeoGebra
When you have greek language enabled and constract several object, GeoGebra names them automatically. When it reaches the letter "π", it should skip it and go on with the next one ("ρ"), since π is a special name. However, it (GeoGebra Classic 5.0.464.0-d) does not, so you end up with an object named "π", which may have strange behaviour.
You can replicate the problem if you make some polygons. Their edges' names are greek letters, as described.